I have a Vice and I'm interested in an FX or an Axe as backup possibilities, but the gun I know the least about of the two is the FX. Can any FX owners who have experience with other markers offer up their take on the gun's performance?

I have never shot either of these guns so take what I have to say with a grain of salt.

That being said some of the differences I know between the Ego 11 platform and the G6R are: The G6R will be cheaper, The G6R will be more efficient, The G6R will require a Ninja Super Low Pressure Tank Regulator for best results, The G6R will be harder to find and come in less color choices than the Ego 11, The G6R does not have a macroline (if you get a leak it will be more costly/problematic to fix but makes for better ergonomics), The G6R packing is not as robust as the Ego 11's, The G6R does not come with an OLED board stock. That's all that's coming to me off the top of my head. As always, check out TechPB Mike's reviews of these guns if you have not already, but either way, no matter what you choose, you are splitting hairs when it comes to top of the line high-end guns like these. There is no wrong or bad choice, only different preferences. The Ego 11 is a Ferrari. The G6R is a Lamborghini. There are no wrong choices, only two right choices. Choose whichever gun best meets your criteria and feels right to you. Can't go wrong!